Aragorn/Thorongil would have to be the focal point, I judge.
[In reply to]

Can't Post

I could see expanding on the story of Aragorn and Arwen in Appendix A, plus the adventures Aragorn had in Rohan and Gondor and Umbar under the assumed name of Thorongil. There's even a hint that Aragorn and Gandalf infiltrated Minas Morgul together. And at some point Aragorn visited Moria and Harad. The story could culminate with Aragorn and Arwen meeting once again in Lothlorien, and plighting their troth. We could also meet Aragorn's mother somewhere along the way. I don't see hobbits coming into that part of the story at all, though, without a significant departure from the appendices.